I think the "dumbed down" perception comes from the new Knowledge Review format. Prior to 2013, the KRs required students to actually write sentences. The new format only requires them to check boxes. Some educators would argue that the ability to write sentences properly is a higher level skill than the ability to check boxes, and that writing sentences requires deeper understanding of the material.
I agree that the course content is improved with the new format, but some OW classes use minimum classroom time: students read the book and bring completed KRs (boxes all checked!) with them to class. For those instructors that spend a lot of time in the classroom, discussing the finer points of the topics, the box-checking format isn't such an issue.